Made of durable ABS plastic our inserts are designed to fit nicely behind photos, bulletin boards, white boards, or one of our Concealment Covers. The shelf can be flipped over and used as a shallow tray if so desired, or can be left out if you prefer to store larger items in your insert. The concept being that you keep a rifle in your bedroom, and a pistol/rifle by your front or rear doors. Of course, in reality you use them as you see fit. Plan the best home defense layout for your home and your desired items. By buying in a bundle instead of individually you will save yourself $15.00.